CN107733170B

CN107733170B - Knowledge of the direction of rotation of a rotor of a rotating electrical machine

Info

Publication number: CN107733170B
Application number: CN201710680048.5A
Authority: CN
Inventors: S·鲍姆加滕; T·伯特格; A·沃尔特
Original assignee: BSH Hausgeraete GmbH
Current assignee: BSH Hausgeraete GmbH
Priority date: 2016-08-10
Filing date: 2017-08-10
Publication date: 2021-04-20
Anticipated expiration: 2037-08-10
Also published as: CN107733170A; DE102016214838A1

Abstract

The invention relates to an electric machine (6), in which a rotor (9) is arranged in a rotatably mounted manner about a rotational axis (10) in an opening (8) which is predetermined by a stator (7) having a stator winding (11) which can be charged with electrical energy, and the rotor (9) has working magnets (12) which are arranged in the circumferential direction of the rotor (9) and which are arranged in such a way that they provide a magnetic field which is directed radially outward and which alternates in the circumferential direction, wherein the axial length of the rotor (9) is greater than the axial length of the stator (7), and the rotor (9) is positioned relative to the stator (7) in such a way that the rotor (9) projects beyond the stator (7) as viewed in the axial direction of the rotational axis (10) in order to form a free region (13), wherein the rotor (9) has a sensor magnet (14) in the free region (13), the sensor magnets are arranged in the circumferential direction of the rotor (9) and provide a magnetic field pointing radially outwards, alternating in the circumferential direction.

Description

Knowledge of the direction of rotation of a rotor of a rotating electrical machine

Technical Field

The invention relates to an electric machine in which a rotor is arranged in a rotatably mounted manner about a rotational axis in an opening predefined by the stator, wherein the stator has a stator winding which can be supplied with electrical energy, and the rotor has working magnets arranged in a working region predefined by the stator winding and in the circumferential direction of the rotor, wherein the working magnets are arranged such that they provide a magnetic field pointing radially outward and alternating in the circumferential direction. The invention further relates to a method for producing a rotor for an electric machine. The invention further relates to a method for determining the direction of rotation of a rotor of an electric machine. The invention further relates to a method for supplying detergents into a lye container of a household appliance for treating laundry, in which method, depending on the release, a first detergent is transferred from a first container by means of a first transfer unit or a second detergent is transferred from a second container by means of a second transfer unit into the lye container. Finally, the invention also relates to a household appliance for conditioning laundry, having a lye container, a first container for a first detergent, a second container for a second detergent, a first delivery unit assigned to the first container for delivering the first detergent into the lye container, and a second delivery unit assigned to the second container for delivering the second detergent into the lye container.

Background

Motors of this type, methods for producing these motors, methods for determining the direction of rotation of the rotor of the motor, methods for supplying detergent into a lye container of a household appliance for care of laundry, and household appliances for care of laundry are known in principle widely from the prior art, so that no special written evidence is required for this purpose. Such motors are currently in particular single-phase synchronous motors, which are preferably designed as claw pole motors. The motor is preferably designed with a permanently excited rotor as an inner pole motor. In particular, when operating the electric machine on a single-phase power supply network, in such electric machines of the prior art it is provided that a predetermined direction of rotation is assumed by the rotor when starting the electric machine by means of a suitable mechanical device. Such devices are expensive, costly and require installation space. Therefore, this type of motor is generally used in a field that does not depend on the rotation direction of the rotor.

A claw pole motor is a rotating motor which is embodied as a single-phase motor and can preferably be designed for low rotational speeds. Due to its type of construction, a claw pole machine is a cost-effective embodiment of a synchronous machine. The claw pole motor can therefore be used particularly advantageously for carrying out the drive task in a household appliance for the care of laundry. In such a household appliance, it can be provided, for example, that a delivery unit for a container in which the washing agent is arranged is driven by means of such a claw pole motor. The conveying unit may for this purpose comprise, for example, a worm conveyor or the like, which may be driven by means of a rotor of an electric motor. Such a motor is preferably very compact and cost-effective to construct and only needs to be constructed for low rotational speeds.

With an increasing functional range, it is provided in household appliances of this type that the detergent for more than one washing process is present in a container provided for this purpose. During the washing process, the washing agent is fed to the lye container as required. Furthermore, such new household appliances have two containers for the first and second detergent, respectively, which containers each comprise their own delivery unit. Each of the transport units is driven by means of its own motor. This makes it possible to dispense with the need to introduce the washing agent into the respective container individually for each washing process. Depending on the laundry to be treated, it is sufficient if the user selects and releases only the detergent suitable for treating the laundry provided. After the start of the care process, the appropriate amount of released detergent is automatically supplied to the lye container.

Even though such prior art has proven effective, there is still a need for improvement. It has therefore proven to be disadvantageous that two separate motors are required for the two transport units of the container of the household appliance.

Disclosure of Invention

The task of the invention is therefore to: the inventive household appliance is improved in such a way that the consumption for supplying the washing agent can be reduced, and a corresponding method is described. In this respect, the invention also has the following tasks: an electric machine of this type and a method for producing and operating such an electric machine are improved.

As a solution, the invention provides a motor, a method for producing a rotor for a motor, a method for determining a direction of rotation of a rotor of a motor, a method for supplying detergent into a lye container of a household appliance for treating laundry, and a household appliance for treating laundry according to the independent claims.

Further advantageous embodiments are obtained by the features of the dependent claims.

In particular, with regard to this type of electric machine: the axial length of the rotor in the direction of the axis of rotation is greater than the axial length of the stator in the direction of the axis of rotation, and, viewed in the axial direction of the axis of rotation, the rotor is positioned relative to the stator such that the rotor projects beyond the stator in order to form a free region, wherein the rotor has sensor magnets in the free region, which are arranged in the circumferential direction of the rotor and provide a magnetic field which is directed radially outward and which alternates in the circumferential direction.

The invention makes it possible to recognize the direction of rotation of the rotor in a simple manner by means of such a structural design of the motor and to make full use of the recognized direction of rotation in order to be able to selectively drive, for example, one of the delivery units of two containers of a household appliance for the care of laundry or the like. Thus, the household appliance also only needs to have a single motor for the aforementioned purpose of delivering the detergent into the lye container. This reduces costs and also increases reliability. By means of a sensor magnet arranged on the rotor of the electric machine, it is possible to sense the magnetic field in the region of the sensor magnet by means of a suitable sensor unit designed for sensing the magnetic field, and the direction of rotation can be determined from the sensor values of the sensor unit. In this case, it has proven to be particularly advantageous to arrange the sensor magnet outside the working region formed by the stator winding in such a way that the magnetic field of the sensor magnet is impeded as little as possible by the magnetic field of the stator winding. Thereby enabling accurate and rapid sensing of the direction of rotation.

The invention takes into account in particular that it is preferably provided here for an electric machine which is operated on a single-phase ac voltage network not to provide a preferred direction of rotor start-up. The invention particularly contemplates that the electric machine does not comprise a device for predetermining the starting direction of the rotor in a predetermined direction of rotation. In this type of motor, therefore, the starting of the rotor takes place randomly in one of the two possible directions of rotation. Since the two delivery units are selectively coupled in rotation direction to the rotor of the motor, the delivery of the detergent from a respective one of the two containers is randomly performed.

In order to avoid this, the invention proposes a method for determining the direction of rotation of the rotor of the electric machine according to the invention, wherein the direction of rotation of the rotor is determined, in particular, by means of a sensor unit having two sensor elements, which is arranged so as to be rotationally fixed relative to the rotor. It is now possible to determine the direction of rotation of the rotor already at the start-up when the rotor has not yet performed a complete revolution. This makes it possible to know the direction of rotation of the rotor early and, when the known direction of rotation does not correspond to the direction of rotation that causes the delivery of the released detergent, to switch off the motor until the rotor has reached zero rotational speed and then to restart the motor. By repeatedly starting the electric motor from a standstill, a desired direction of rotation of the rotor can be achieved after a limited number of attempts, so that the operation of the electric motor can then continue for so long as a desired amount of the released detergent is delivered into the lye container of the household appliance.

The invention is of course not limited to an application for driving a transport unit for transporting detergent from a container into a lye container. Likewise, such a motor can of course also be used in other corresponding devices, when different functions are to be carried out in different directions of rotation.

For example, the sensor elements of the sensor unit can be arranged in the circumferential direction at a distance from one another which is less than approximately half the average distance between two adjacent sensor magnets. It is thereby possible to ascertain the direction of rotation of the rotor already with a slight rotational movement of the rotor by evaluating the sensor signals of the sensor elements. For this purpose, the sensor element can be designed, for example, as a hall sensor, an induction coil, a combination of the above, or the like. The sensor element or sensor unit can be connected to a control unit, to which the electric motor can also be connected, in order to be able to control its operation. The average distance is preferably the length of an arc of the rotor in the circumferential direction, which arc is delimited by the respective radial center lines of the, in particular, directly adjacent sensor magnets. Preferably, the spacing is a corresponding arc length. The pitch may in particular be about half the average pitch. However, the spacing can also be formed substantially by a straight line, in particular if the spacing is smaller than the radial spacing from the rotor axis of rotation. The distance should be adjusted such that the sensor signals, in particular the alternating voltages supplied as sensor signals, have a phase difference in the range from greater than zero to less than 180 °.

Preferably, the sensor element is positioned relative to the rotor such that it can sense the magnetic field of the sensor magnet. For this purpose, it can be provided that the sensor element is arranged in a rotationally fixed manner with a predetermined clearance in the circumferential direction, radially spaced apart from the sensor magnet. For this purpose, the sensor element or sensor unit can be arranged in a housing which is fixed to the stator axially adjacent to the stator winding.

The sensor magnet can be formed, for example, by a magnetizable element which is correspondingly magnetized and thus forms a permanent magnet. The permanent magnets can then be arranged circumferentially on the rotor with alternating polarity with respect to the magnetic field in the free region. Furthermore, there are of course the following possibilities: the sensor magnet is also formed by suitable electrical coils which are supplied with a direct current in order to be able to provide the magnetic field in a predetermined manner. Combinations thereof may also be provided.

Electrical machines, in particular rotating electrical machines, are such devices: in this device, the stator provides a generally circular opening into which the rotor is rotatably supportably arranged. In contrast to the rotor, the stator is arranged rotationally fixed, so that the stator is fixedly connected to a support, such as a base, a housing or the like, for example, so that it usually does not execute a rotational movement. Nevertheless, the electric machine and thus the stator can of course also be arranged movably, for example on a vehicle or the like.

The stator and the rotor are interlinked by means of a magnetic flow, whereby a force action is generated during operation of the motor, which force action drives the rotor into rotation relative to the stator. For this purpose, the stator has a stator winding through which a current flows. In this connection, permanent magnets are provided as working magnets in the rotor. The rotor winding can of course also be provided on the rotor side in addition, in order to be able to shape the magnetic field in the desired manner. This type of machine is designed for connection to a single-phase network. However, the electric machine can also be formed essentially by a correspondingly suitable direct current machine, for example a shunt machine, a series machine, a stepping motor and/or the like.

The rotor is therefore a movable, in particular rotatable, unit in the sense of the present disclosure, which is designed in the electric machine according to the type of rotor. The stator or stator is usually arranged in a stationary position relative to a housing of the appliance, for example a household appliance, or a base connected to the floor.

The rotor is driven in rotation by the magnetic flux linkage of the rotor and the stator, as a result of the stator winding being loaded with electrical energy. For this purpose, the magnetic field generated by the stator windings acts on the magnetic field provided by the working magnets of the rotor. In order to allow the rotor to rotate relative to the stator, a gap is formed between the stator winding and the rotor, in particular the working magnets of the rotor. In order to be able to achieve good magnetic linkage of the magnetic flow, the gap is designed to be as small as possible. The working magnet can be formed, like the sensor magnet, by magnetizable elements which are magnetized by applying a magnetic field having a predetermined magnetic flux density, so that the magnetizable elements also form permanent magnets. For this purpose, the magnetizable element can be formed from a magnetizable material, for example from a hard magnetic material such as an alloy consisting of iron, cobalt, nickel or ferrite or the like. The permanent magnet has and contains a static magnetic field which is maintained independently of an external energy supply. Further, materials suitable as materials for the permanent magnet are alloys composed of aluminum with nickel and cobalt, alloys composed of bismuth, manganese and iron, alloys composed of neodymium, iron and boron, alloys composed of samarium and cobalt, and ferrite materials and/or the like. Furthermore, non-metallic, organic synthetic materials having permanent magnetic properties, such as the synthetic magnet material PANiCNQ, which has ferrimagnetic properties, for example at room temperature, are also considered as materials for the working magnet and/or the sensor magnet.

In order to achieve a good interlinkage of the magnetic field of the rotor with the magnetic field of the stator winding, the magnetic field of the rotor is preferably oriented radially. Accordingly, the working magnets are arranged in a suitable manner such that they provide a radially oriented magnetic field alternating in the circumferential direction.

In order to be able to achieve a low rotational speed of the rotor during the intended operation of the electric machine, a correspondingly large number of pole pairs of the pole pairs can be provided, which pole pairs are formed by the working magnets. The greater the number of pole pairs provided by the working magnets, the lower the rotational speed of the rotor in proper operation can be. The stator winding is preferably configured to be adapted accordingly.

The present invention utilizes the following recognition: the sensing of the magnetic field provided by the sensor magnet should be performed as undisturbed as possible. For this purpose, it is provided that the sensor magnet is preferably arranged on the rotor at a distance from the stator winding, in particular from the entire stator, so that the magnetic field of the sensor magnet can be sensed by the sensor unit or the sensor elements of the sensor unit as far as possible without being disturbed by the magnetic field of the stator winding. The sensing of the direction of rotation of the rotor can thereby be carried out with high accuracy and very quickly at the start of the rotor, so that it can be avoided that, for example, during the start of the rotor in order to convey detergent from the container during use, detergent which is not released detergent due to the actually performed rotational movement of the rotor is already conveyed into the lye container. The invention makes it possible to know the direction of rotation of the rotor already after the rotational movement has been carried out for a pair of angles during starting and to initiate a corresponding control of the electric machine. If this direction of rotation is not the desired direction of rotation, the electric machine can be switched off directly by means of the control unit without the rotor having to be accelerated to its prescribed operating speed. The influence of the undesired direction of rotation can thereby be kept low, or even avoided if it is completely undesired.

For this reason, the invention provides that the axial length of the rotor in the direction of the axis of rotation is greater than the axial length of the stator in the direction of the axis of rotation, and that the rotor, viewed in the axial direction of the axis of rotation, is positioned relative to the stator such that the rotor projects beyond the stator so as to form a free region. The free region is preferably selected such that the magnetic field effect of the stator winding is substantially negligible when sensing the magnetic field of the sensor magnet. The magnetism of the sensor magnet can thus be sensed preferentially in this regionField and substantially undisturbed. For this reason, the invention also provides that the rotor has a sensor magnet in the free region. The sensor magnets are arranged in the circumferential direction of the rotor and likewise provide a radially outwardly directed magnetic field which alternates in the circumferential direction. The number of sensor magnets in the circumferential direction may correspond to a desired resolution

Is chosen such that as fast a sense of the direction of rotation as possible can be achieved. In this case, the sensor magnet does not need to be designed for the magnetic flux density that the working magnet should provide. The magnetic flux density can therefore be selected such that a reliable sensing of the magnetic field can be achieved by means of the sensor unit or its sensor elements.

Preferably, it is provided that the radius of the rotor in the region in which the working magnet is arranged corresponds to the radius of the rotor in the region in which the sensor magnet is arranged. This makes it possible to provide a rotor that is uniform in the circumferential direction with respect to the outer dimensions, so that a simple assembly of the rotor and also a simplified production of the rotor can be achieved.

Furthermore, it is proposed that the sensor magnet and the working magnet are arranged at a distance from one another in the direction of the axis of rotation. The working region predefined by the stator winding can thereby be spatially separated from the free region in which the sensor magnet is arranged on the rotor, so that disturbances with respect to the magnetic field measurement of the sensor magnet can be largely avoided. Preferably, the distance is selected such that the stray field of the stator winding does not substantially interfere with the measurement of the magnetic field in the region of the free region.

Furthermore, it is naturally also possible to provide that the sensor magnet is formed integrally with the working magnet. Preferably, it can be provided here that the axial extent of the rotor in the direction of the axis of rotation is selected such that the working magnet projects into the free region in order to simultaneously form the sensor magnet. A separate sensor magnet can thus be dispensed with. At the same time, this configuration also enables a simplified production of the rotor, since only the working magnet, which likewise forms the sensor magnet, is to be arranged on the rotor.

According to an advantageous configuration, it is provided that the sensor magnet and/or the working magnet are formed by a correspondingly magnetized magnet ring. This makes it possible to provide only one element for the sensor magnet or the working magnet on the rotor. The invention thus makes it possible to further reduce assembly costs and costs relating to manufacture. It is of course also possible to provide a common, correspondingly magnetized magnet ring for the sensor magnet and the working magnet. This configuration is particularly advantageous and cost-effective with regard to the assembly expenditure and production, in particular in the case of small electric machines.

According to a further embodiment of the invention, the free region is delimited in the direction of the rotational axis by an end-side end of the rotor, which end provides a varying axial length of the rotor in the circumferential direction. This configuration makes it possible to influence the magnetic field provided by the sensor magnet. For this purpose, the material forming the rotor is formed at least partially from ferromagnetic material, so that the course of the magnetic field of the sensor magnet in the circumferential direction can be influenced by the shaping of the end faces. Preferably, the end-side end can be designed in such a way that an almost sinusoidal magnetic flux density variation can be achieved in the sensor magnet region in the circumferential direction. This allows the sensor unit or sensor element to know the direction of rotation already when the rotor is rotated only a few degrees. Therefore, the accuracy of the rotational direction sensing and the resolution of the rotational direction sensing can be significantly improved. This configuration can be combined with a sensor magnet formed by a magnetic ring. Preferably, the magnet ring can also delimit the end face end of the rotor.

It is also proposed that the end-side end has a coupling element. The coupling element can thus be constructed together with the free region. The free region can be formed in particular integrally with the coupling element. However, it is also possible to arrange the coupling element as a separate component, for example fixed to the end face end. Furthermore, a combination of these can be provided in that the coupling element is at least partially formed integrally with the rotor, in particular the rotor end face end, and has a separable part. The coupling element can in particular have a magnetizable material, for example a magnet of the type bonded according to a synthetic material, in order to thus, for example, form a sensor magnet. The advantage is the simple production of the component, since the assembly and/or the injection molding of the individual parts can be dispensed with. The magnetic ring carrier can in particular be made entirely of a magnet material, preferably joined by a synthetic material.

Furthermore, the invention proposes, in particular, a method for producing a rotor for an electrical machine according to the invention, wherein, in the circumferential direction of the rotor, a first magnetizable element is arranged on the rotor in a working region predefined by the stator winding and a second magnetizable element is arranged in a free region, wherein the first magnetizable element is magnetized by means of an external magnetic field in such a way that the first magnetizable element provides a radially outwardly directed magnetic field alternating in the circumferential direction as a working magnet and/or the second magnetizable element is magnetized by means of an external magnetic field in such a way that the second magnetizable element provides a radially outwardly directed magnetic field alternating in the circumferential direction as a sensor element. In this way, a rotor for an electric machine according to the invention can be produced in a simple manner, in which rotor the unmagnetized magnetizable elements are arranged on the rotor. Only when the magnetizable element is arranged, for example fixed, on the rotor, the magnetizable element is magnetized in the desired manner by the action of the external magnetic field in order to provide pole pairs with respect to the working magnet. The external magnetic field is oriented in such a way that the magnetizable first element provides, as a working magnet, a radially outwardly directed magnetic field alternating in the circumferential direction. Accordingly, provision can also be made for a magnetizable second element, which, by means of a corresponding magnetization based on an external magnetic field, likewise provides, as a sensor magnet, a magnetic field pointing radially outward and alternating in the circumferential direction. Preferably, these two configurations are combined with each other so that the sensor magnet can also be provided in the same device in which the working magnet is provided.

The external magnetic field is preferably provided by means of an air coil whose magnetic field is delimited by the spatial angle determined by the magnetizable first and/or second element with respect to the axis of rotation of the rotor. It is thereby possible to provide alternating polarities of the working magnet and/or of the sensor magnet in the circumferential direction. The coil is in particular part of a magnetization device, by means of which the magnetizable element is magnetized in the desired manner. Depending on the application, the coil may also have a ferromagnetic core. The external magnetic field is preferably limited to the region in which the desired orientation of the magnetizable first and/or second element is desired. The air coil can of course also be formed by a plurality of individual coils arranged in the circumferential direction of the rotor, which coils simultaneously provide an external magnetic field corresponding to the desired number of pole pairs. It is thus possible to provide the entire working magnet and/or also the sensor magnet in one working step.

Preferably, the first and second magnetisable elements are magnetised simultaneously. A further simplification of the production method can be achieved in that all magnets, that is to say all working magnets and all sensor magnets, can also be provided in a single production step.

It has proven to be particularly advantageous if the first and/or the second magnetizable element is formed by a magnetizable ring which is correspondingly subjected to an external magnetic field for the purpose of forming the magnet. In this case, a particularly simple manufacture of the rotor can be achieved, since on the one hand only a magnetizable ring needs to be arranged on the rotor, which ring is then magnetized in the desired manner by the external magnetic field, so that a corresponding working magnet or sensor magnet is provided.

According to a further embodiment, it is provided that the first magnetizable element and/or the second magnetizable element are injection-molded by a detergent-and/or moisture-resistant synthetic material. As a result, the magnetizable element can not only be connected to the rotor as a single structural unit, but it can also be protected against external influences during proper operation, for example, when used in a household appliance for the care of laundry, against influences from detergents and moisture or the like. This can improve the reliability of the rotor and the motor as a whole.

In particular, a method for determining the direction of rotation of a rotor of an electric machine is proposed, in which the angle between the radial connecting lines of the sensor element to the rotor axis of rotation is different from the angle between the connecting lines of the sensor magnet to the axis of rotation or from an integer multiple of this angle, and the sensor element is positioned relative to the rotor in such a way that it senses the magnetic field of the sensor magnet, wherein the direction of rotation of the rotor is determined by evaluation of the sensor signals of the sensor element. The sensor elements are therefore preferably arranged at a spacing outside the pole pitch. For example, the sensor elements can be arranged at a distance from one another in the circumferential direction that is smaller than the distance between two adjacent sensor magnets. The so-called pole pitch or pole pitch is determined by adjacent sensor magnets, in particular directly adjacent sensor magnets. The number of pole pairs is the number of pole pairs inside the rotating machine. The spacing between two adjacent sensor magnets is referred to as the pole pitch. Here, the measurement is performed from pole center to pole center. The higher the number of pole pairs, the narrower the sensor magnets are adjacent to each other. The directly adjacent sensor magnets preferably have opposite polarity with respect to the magnetic field provided thereby. The pole pitch therefore relates in particular to the spacing of a sensor magnet providing a north magnetic pole from a directly adjacent sensor magnet providing a south magnetic pole. The distance can preferably be determined by radial center lines, which can each be assigned to a respective sensor magnet with respect to the axis of rotation of the rotor. The sensor elements are preferably arranged relative to one another in such a way that the spacing of the sensor elements in the circumferential direction is not greater than the average spacing of the preferably directly adjacent sensor magnets. It is thereby possible to achieve a high resolution with regard to the direction of rotation of the rotor, so that the direction of rotation of the rotor can already be determined when the rotor makes a small part of a rotation. Particularly preferably, however, the sensor elements are not arranged directly next to one another, but rather are arranged at a predetermined distance, which corresponds, for example, to a range of approximately 20 to approximately 80 percent of the average distance. Preferably, the distance may also correspond to half the average distance between adjacent sensor magnets. The spacing of the sensor elements can be selected adaptively according to the application, in order to be able to achieve a resolution suitable for the respective application.

Preferably, the rotor is started randomly in one direction of rotation when the stator winding is supplied with electrical energy, and the start is repeated so long until the rotor is started in the predetermined direction of rotation. By repeated starting, the electric machine can be restarted any number of times until the rotor assumes the desired direction of rotation for the desired function. In the case of the detergent supply in the household appliance for care of laundry mentioned at the outset, the direction of rotation is used to select the detergent which is to be used for the current care process. By knowing the direction of rotation of the rotor already when it makes a small part of the rotation, it is possible to avoid that undesired washing agent is supplied to the lye container.

Accordingly, with regard to a method for supplying detergent into a lye container of a household appliance for treating laundry, in which method a first detergent is conveyed from a first container into the lye container by means of a first conveying unit or a second detergent is conveyed from a second container into the lye container by means of a second conveying unit as a function of a release, it is proposed in particular that the first conveying unit is driven by the motor of the invention when the rotor is started in a first direction of rotation, the second conveying unit is driven by the motor of the invention when the rotor is started in a second direction of rotation, wherein the rotor is started at random in one of the two directions of rotation when the stator winding is charged with electrical energy, wherein the direction of rotation of the rotor is known by the method of the invention and the starting of the motor is repeated for so long that the rotor is started in a predefined direction of rotation, thereby supplying the detergent from one of the two containers, which is predetermined by the release, to the lye container

Accordingly, the invention proposes, inter alia, a household appliance for the care of laundry, which has a lye container; a first container for a first detergent; a second container for a second detergent; a first delivery unit assigned to the first container and for delivering the first detergent into the lye container; a second delivery unit assigned to the second container and for delivering the second detergent into the lye container; according to the motor of the present invention, for driving the first conveying unit when the rotor is started in the first rotation direction and for driving the second conveying unit when the rotor is started in the second rotation direction; a control unit for controlling the motor to transport the first detergent from the first container into the lye container by means of the first transport unit or the second detergent from the second container by means of the second transport unit in dependence on said release. Preferably, the rotor is started randomly in one of the two rotational directions when the stator windings are loaded with electrical energy. In particular, a sensor unit is provided which has two sensor elements and is connected to a control unit, wherein the sensor elements are arranged at a distance from one another in the circumferential direction which is less than half the average distance between two adjacent sensor magnets, and the sensor elements are positioned relative to the rotor such that they sense the magnetic field of the sensor magnets, wherein the control unit is designed to determine the direction of rotation of the rotor by evaluating the sensor signals of the sensor elements and to repeat the starting of the motor for a long time until the rotor is started in a predefined direction of rotation in order to supply detergent from one of the two containers which is predefined by the release into the lye container.

Further features of the invention emerge from the claims, the figures and the description of the figures. The features and feature combinations mentioned above in the description and those mentioned in the following description of the figures and/or shown in the figures individually can be used not only in the respectively stated combination but also in other combinations without leaving the scope of the invention. The following embodiments are therefore also to be considered as being encompassed and disclosed by the present invention, which embodiments are not explicitly shown and described in the drawings, but are known from and can be produced from the illustrated embodiments by means of separate combinations of features. Thus, embodiments and combinations of features not having all the features of the originally drafted independent claims should also be considered disclosed. Furthermore, combinations of features beyond those set forth in the claims or embodiments and combinations of features deviating therefrom, in particular combinations of features formed by the above-described embodiments, are to be regarded as disclosed.

Drawings

The figures show:

figure 1 shows a washing machine according to the invention as a domestic appliance in a schematic open front view,

figure 2 shows in a schematic circuit diagram a claw-pole motor for driving a delivery unit assigned to a detergent container of the washing machine according to figure 1,

figure 3 a schematic longitudinal section through a claw-pole machine according to figure 2,

figure 4 shows a first configuration in schematic cross-section for a rotor of a claw pole machine according to figure 2,

fig. 5 shows a second configuration in schematic section for a rotor of a claw-pole machine according to fig. 2, an

Fig. 6 shows a third configuration in a schematic sectional view of a rotor for a claw pole machine according to fig. 2.

Detailed Description

Fig. 1 shows a washing machine 1 as a domestic appliance for the care of laundry in a schematic open front view. The washing machine 1 shown in fig. 1 has a rotatably mounted washing machine drum 3, which can be driven by means of a drive unit 17 via a drive belt 16. The drive unit 17 is connected to the control unit 4 via an energy connection 18. Furthermore, the drive unit 17 is connected to the control unit 4 of the washing machine 1 via a control line 19. The control unit 4 is connected in a manner not shown in detail to a power supply network, here to a common power supply network 27, which supplies a single-phase supply voltage. In order to operate the washing machine 1, a common energy supply network provides the required electrical energy. Not shown, the drive unit 17 comprises a transformer by means of which the rotational speed and the torque of the washing machine drum 3 can be adjusted in a desired manner.

The washing machine drum 3 provides a receiving chamber for the laundry to be cleaned, which can be closed by means of the door 2, as a housework object. The washing machine drum 3 is arranged in a lye container 5 of the washing machine 1. Furthermore, the control unit 4 serves to operate further devices of the washing machine 1 during a defined period of use, here during a washing process. For this purpose, the control unit 4 comprises a computer unit 15, which is designed here as a microprocessor.

Furthermore, the washing machine 1 comprises a locking device, not shown, by means of which the door 2 can be locked in the closed door position. In the locked state, the door 2 can no longer be opened manually by the user.

Furthermore, the locking device can be controlled by means of the control unit 4 in order to unlock the door 2, so that manual actuation of the door by the user is again released. This relates in particular to the opening of the door 2 after the end of the washing process.

Furthermore, fig. 1 shows a first container 25 for a first detergent and a second container 26 for a second detergent. As cannot be seen from the figure, the washing machine 1 comprises a first delivery unit assigned to the first container 25 for delivering a first detergent into the lye container 5 and a second delivery unit assigned to the second container 26 for delivering a second detergent into the lye container 5. The conveying units each have a worm conveyor, by means of which the respective detergent can be conveyed from the respective one of the

containers

25, 26 into the lye container 5. For this purpose, the worm conveyor can be selectively driven in rotation, as required, by means of a single motor 6, which is here configured as a claw-pole motor according to the type of internal rotor motor. The motor 6 is electrically connected to and controlled by the control unit 4. Furthermore, coupling units, by means of which the rotor 9 of the electric motor 6 can be coupled in rotation with the respective worm drives according to its direction of rotation, are not shown in the figures. A worm conveyor is provided only by way of example in this embodiment. Alternatively, other conveying elements can of course also be provided, which can be driven correspondingly by means of the motor 6.

Fig. 2 and 3 show respective schematic views of the electric machine 6. Fig. 2 shows a section of the electric machine 6 transversely to the axis of rotation 10 of the rotor 9 in a working region which is predefined by the stator windings 11 of the stator 7 of the electric machine 6. Furthermore, the stator 7 defines an opening 8 in which a rotor 9 is rotatably mounted about a rotational axis 10. The stator windings can be supplied with electrical energy.

The rotor 9 has working magnets 12, which are designed here as permanent magnets, arranged in a predetermined working region and in the circumferential direction of the rotor 9. The working magnets 12 are arranged in such a way that they provide a radially outwardly directed magnetic field that alternates in the circumferential direction. As can be seen from fig. 2, the electric machine 6 is designed as a four-pole machine with two pole pairs.

Fig. 3 shows a schematic side view of the motor 6. It can thus be seen that the axial length of the rotor 9 in the direction of the axis of rotation 10 is greater than the axial length of the stator 7 in the direction of the axis of rotation 10, and that, viewed in the axial direction of the axis of rotation 10, the rotor 9 is positioned relative to the stator 7 such that the rotor 9 projects beyond the stator 7 in order to form a free region 13. The rotor 9 has sensor magnets 14 in the free region 13, which are arranged in the circumferential direction of the rotor 9 and provide a magnetic field pointing radially outward that alternates in the circumferential direction. As with the working magnet 12, even if provided in the sensor magnet 14, the directly adjacent ones of these magnets provide opposing magnetic fields. The sensor magnet 14 is also designed here as a permanent magnet.

Furthermore, it can be seen from fig. 2 and 3 that a gap 28 is formed between the stator winding 11 and the rotor 9, so that the rotor 9 can rotate freely in the opening 8. The magnetic currents of the stator winding 11 and the working magnets 12 are interlinked via the air gap 28 in a predetermined working region by the stator winding 11, so that the rotor 9 has a predetermined rotational speed after a start-up process in a proper operation. For this purpose, the stator windings 11 are supplied with electrical energy from an energy supply network 27 by the control unit 4.

Fig. 4 shows a first embodiment of the rotor 9 of the electric machine 6 in a schematic longitudinal section. It can be seen that the radius of the rotor 9 in the region of the working magnet 12 is greater than the radius in the free region 13, in which the sensor magnet 14 is arranged.

Fig. 5 shows a further embodiment of the rotor 9 of the electric machine 6, in which the rotor 9 has the same radius in the region of the sensor magnet 14 and the working magnet 12. Not shown in fig. 4 and 5 are coupling elements provided at the axial ends, by means of which the rotor 9 can be connected in terms of rotation to a worm conveyor of a coupling unit or a conveying unit. In contrast, such a coupling element of the rotor 9 is shown in fig. 3, wherein the coupling element 29 is arranged at the end opposite the free region 13 of the rotor 9.

As cannot be seen from fig. 4 and 5, the working magnet 12 and the sensor magnet 14 are each formed by a correspondingly magnetized ring of magnetizable material. In this regard, the sensor magnet 14 and the working magnet 12 are each formed in one piece.

Furthermore, it can be seen from fig. 4 and 5 that the sensor magnet 14 and the working magnet 12 are magnetized by means of an external magnetic field for proper operation in the area of the production of the rotor 9. For this purpose, a magnetizing coil 21 is provided, by means of which a required external magnetic field can be provided in order to magnetize the magnetized ring in a predetermined manner in order to form the working magnet 12 and the sensor magnet 14.

To produce the rotor 9 for the electric machine 6, therefore, a first magnetizable element, in this case a first magnetizable ring, is arranged on the rotor 9 in the circumferential direction of the rotor 9 in a working region predetermined by the stator windings 11, and a second magnetizable element, in this case a second magnetizable ring, is arranged in the free region 13. The first magnetizable ring is then magnetized by means of an external magnetic field in such a way that it forms a working magnet 12 which provides a radially outwardly directed magnetic field alternating in the circumferential direction. Furthermore, the second magnetizable ring is magnetized by means of an external magnetic field in such a way that it forms the sensor magnet 14, so that the sensor magnet 14 provides a magnetic field pointing radially outward that alternates in the circumferential direction.

For this purpose, it is provided that an external magnetic field is provided by means of an air coil 21, whose magnetic field is delimited by the spatial angle, defined by the respective magnetizable first element or the respective magnetizable second element, with respect to the axis of rotation 10 of the rotor 9. It is thereby possible for the respective magnetizable ring to be provided with a plurality of poles, so that the working magnet 12 or the sensor magnet 14 can be provided by the respective magnetizable ring.

In the embodiments according to fig. 4 and 5, it is provided that the magnetizable first and second rings are magnetized simultaneously. It is thus possible to provide both the working magnet 12 and the sensor magnet 14 in a single process step.

Before or after the magnetization of the magnetizable ring, it can be provided that the working magnet 12 and the sensor magnet 14 are encapsulated by a detergent-and moisture-resistant plastic. The rotor 9 is thus designed in a protected manner against influences due to moisture and detergent, so that it is reliably installed in the washing machine 1 for proper operation.

Fig. 3 also shows a sensor unit 24, which is arranged so as to be rotationally fixed relative to the rotor 9 and has two

sensor elements

22, 23 and which is fixed here to an unmarked housing of the electric machine 6. The sensor unit 24 is arranged opposite the free region 13 of the rotor 9, so that the

sensor elements

22, 23 can sense the magnetic field provided by the sensor magnet 14 as far as possible without interference from the magnetic field of the stator winding 11. It is provided here that the

sensor elements

22, 23 are formed by hall sensors and are arranged at a distance from one another in the circumferential direction which is less than half the average distance between two directly adjacent sensor magnets 14. The

sensor elements

22, 23 provide sensor signals which are transmitted to the control unit 4. The control unit 4 evaluates the sensor signals and knows the direction of rotation of the rotor 9 from them.

The motor 6 has the following characteristics: when the stator winding 11 is supplied with electrical energy, the rotor 9 starts at random in its two possible directions of rotation. However, since the washing machine 1 requires a predefined direction of rotation of the rotor 9 for proper operation thereof in order to be able to feed the released detergent from the

respective container

25, 26 into the lye container 5, the activation of the rotor 9 is repeated by means of the control unit 4 for so long as the rotor 9 is activated in the predefined direction of rotation. This direction of rotation corresponds to a predefined direction of rotation: in this direction of rotation, the delivery unit of the one of the

containers

25 and 26 containing the released detergent is driven.

Furthermore, in the present embodiment, it is provided that the start-up of the rotor 9 is repeated at most three times. That is, it has been shown that the desired direction of rotation can be achieved with high reliability after this number of repeated starts for the application set. However, depending on the detailed design of the electric machine 6 and, if applicable, also depending on the application, it can also be provided that the maximum number of repeated starts is limited, for example, to 4, in particular to 5, or also to a larger number.

Fig. 6 shows a further embodiment of the electric machine 6, in which the working magnet 12 and the sensor magnet 14 are formed integrally with one another. In this embodiment, it is also provided that the free region 13 is delimited in the direction of the rotational axis 10 by an end-side end 20 of the rotor 9, which end provides a varying axial length of the rotor 9 in the circumferential direction. It is provided here that the structure formed thereby has a circumferential wave form which is designed in such a way that, by means of the sensor unit 24, a sinusoidal change of the magnetic field can be sensed as a function of the rotational position of the rotor 9.

This configuration is also characterized in that it can be realized in a particularly simple manner. By means of the free region 13, it is simultaneously possible to: the sensor unit 24 is substantially undisturbed by the magnetic field of the stator winding 11. The sensor magnetic field can therefore be reliably sensed by means of the sensor unit 24, so that the control unit 4 can likewise know the direction of rotation of the rotor 9 even in the case of very small rotations. The rotor 9 does not need to be accelerated to the operating rotational speed at which it is set in the intended operation in order to be able to detect its direction of rotation. Thereby, not only a very fast sensing of the rotational direction of the rotor 9 is possible, but also a very fast method flow with respect to repeated starting of the rotor 9 until a desired rotational direction of the rotor 9 is achieved. This makes it possible to achieve a very reliable and ergonomically advantageous control.

The features and advantages described in connection with the electric motor 6 and the method for producing the same and for ascertaining the direction of rotation of the rotor 9 of the electric motor can also be applied to the household appliance 1 according to the invention for the care of laundry and to the corresponding method for operating the household appliance. In particular, corresponding device features can also be provided for method features and vice versa.

The invention is of course not limited to application in washing machines, as regards the motor 6 and the method of manufacturing the rotor for the motor and the method for knowing the direction of rotation. These aspects can of course also be used in particular in other devices in which different units are to be driven by means of different directions of rotation.

The foregoing examples are provided merely to illustrate the invention and are not intended to be limiting. The function, in particular the realization of the magnets, the structure of the motor and the like, can of course be modified at will without leaving the original idea of the invention. The advantages and features and embodiments described for the electric machine according to the invention apply equally to the household appliance according to the invention and to the method according to the invention and vice versa.

List of reference numerals

1 washing machine

2 door

3 washing machine drum

4 control unit

5 lye container

6 tooth-shaped electrode motor

7 stator

8 opening

9 rotor

10 axis of rotation

11 stator winding

12 working magnet

13 free region

14 sensor magnet

15 computer unit

16 drive belt

17 drive unit

18 energy joint

19 control conductor

20 end of

21 air core coil

22 sensor element

23 sensor element

24 sensor unit

25 container

26 container

27 energy supply net

28 gap

29 coupling element

Claims

1. An electric machine (6) in which a rotor (9) is arranged in a rotatably mounted manner about a rotational axis (10) in an opening (8) predefined by a stator (7), wherein the stator (7) has a stator winding (11) which can be charged with electrical energy, and the rotor (9) has working magnets (12) which are arranged in a working region predefined by the stator winding (11) and are arranged in the circumferential direction of the rotor (9), wherein the working magnets (12) are arranged such that they provide a radially outwardly directed magnetic field which alternates in the circumferential direction, characterized in that the axial length of the rotor (9) in the direction of the rotational axis (10) is greater than the axial length of the stator (7) in the direction of the rotational axis (10), and the rotor (9) is positioned relative to the stator (7) as viewed in the axial direction of the rotational axis (10) such that the rotor (9) protrudes beyond the stator (7) in order to form a free region (13), wherein the rotor (9) has a sensor magnet (14) in the free region (13), which sensor magnet is arranged in the circumferential direction of the rotor (9) and provides a magnetic field which is directed radially outward and which alternates in the circumferential direction, wherein a sensor unit (24) having two sensor elements (22, 23) is provided, wherein the sensor elements (22, 23) are arranged at a distance from one another in the circumferential direction, in which case the angle between the respective radial connecting lines of the two sensor elements (22, 23) to the rotational axis (10) of the rotor (9) differs from the angle between the respective radial connecting lines of the two sensor magnets (14) to the rotational axis (10) of the rotor (9) The angle between the respective connecting lines of the axes of rotation (10) is different from an integer multiple of this angle.

2. The electrical machine according to claim 1, characterized in that the radius of the rotor (9) in the region in which the working magnet (12) is arranged corresponds to the radius of the rotor (9) in the region in which the sensor magnet (14) is arranged.

3. The electrical machine according to claim 1 or 2, characterized in that the sensor magnet (14) and the working magnet (12) are arranged spaced apart from one another in the direction of the axis of rotation (10), or in that the sensor magnet (14) is constructed in one piece with the working magnet (12).

4. The electrical machine according to claim 1 or 2, characterized in that the sensor magnet (14) and/or the working magnet (12) are formed by a correspondingly magnetized magnet ring.

5. The electrical machine according to claim 1 or 2, characterized in that the free region (13) is delimited in the direction of the axis of rotation (10) by an end-side end (20) of the rotor (9) which provides a varying axial length of the rotor (9) in the circumferential direction.

6. The machine according to claim 5, characterized in that the end-side end (20) has a coupling element (29).

7. Method for manufacturing a rotor (9) for an electrical machine (6) according to any of the preceding claims, wherein, on the rotor (9) in the circumferential direction of the rotor (9), a first element that can be magnetized is arranged in a working region predetermined by the stator winding (11) and a second element that can be magnetized is arranged in the free region (13), wherein the first magnetizable element is magnetized by means of an external magnetic field in such a way that it provides, as a working magnet (12), a magnetic field pointing radially outwards that alternates in the circumferential direction, and/or the second magnetizable element is magnetized by means of the external magnetic field in such a way that it provides a radially outwardly directed magnetic field alternating in the circumferential direction as a sensor magnet (14).

8. Method according to claim 7, characterized in that the external magnetic field is provided by means of an air coil (21) whose magnetic field is delimited by the spatial angle determined by the first and/or second magnetizable element with respect to the axis of rotation (10) of the rotor (9).

9. The method according to claim 7 or 8, wherein the first and second magnetizable elements are magnetized simultaneously.

10. Method according to claim 7 or 8, characterized in that the first and/or the second magnetizable element is/are formed by a magnetizable ring which is correspondingly loaded with the external magnetic field in order to form the working magnet (12) and the sensor magnet (14).

11. Method according to claim 7 or 8, characterized in that the first and/or the second magnetizable element is/are injection-molded in a detergent-and/or moisture-resistant synthetic material.

12. Method for ascertaining the direction of rotation of a rotor (9) of an electric machine (6) according to one of claims 1 to 6, characterized in that the direction of rotation of the rotor (9) is ascertained by means of a sensor unit (24) which is arranged rotationally fixed relative to the rotor (9) and has two sensor elements (22, 23), wherein the sensor elements (22, 23) are arranged at a distance from one another in the circumferential direction, in which case the angle between the respective radial connecting lines of the two sensor elements (22, 23) to the axis of rotation (10) of the rotor (9) differs from the angle between the respective connecting lines of the two sensor magnets (14) to the axis of rotation (10) or from an integer multiple of this angle, and the sensor elements (22, 23) are positioned in such a way relative to the rotor (9), the sensor element is designed to sense the magnetic field of the sensor magnet (14), wherein the direction of rotation of the rotor (9) is determined by evaluation of the sensor signals of the sensor element (22, 23).

13. Method according to claim 12, characterized in that the rotor (9) is started randomly in one direction of rotation when the stator winding (11) is charged with electrical energy and the start is repeated so long until the rotor (9) starts in the predetermined direction of rotation.

14. Method for supplying detergent into a lye container (5) of a household appliance (1) for caring for laundry, in which method a first detergent is delivered from a first container (25) into the lye container (5) by means of a first delivery unit or a second detergent is delivered from a second container (26) into the lye container (5) by means of a second delivery unit upon release, wherein the first delivery unit is driven by a motor (6) according to any one of claims 1 to 6 when the rotor (9) is started in a first direction of rotation and the second delivery unit is driven by the motor (6) when the rotor (9) is started in a second direction of rotation, wherein the rotor (9) is started randomly in one of the two directions of rotation when the stator winding (11) is charged with electrical energy, wherein, the direction of rotation of the rotor (9) is determined by the method according to claim 12 or 13, and the starting of the electric motor (6) is repeated so long until the rotor (9) is started in a predetermined direction of rotation, whereby the detergent is supplied from the one of the first and second containers (25, 26) which is predetermined by the release into the lye container (5).

15. A household appliance (1) for care of laundry, having a lye container (5); a first container (25) for a first detergent; a second container (26) for a second detergent; a first feeding unit assigned to the first container (25) for feeding the first detergent into the lye container (5); a second feeding unit assigned to the second container (26) for feeding the second detergent into the lye container (5); the motor (6) according to any of claims 1 to 6, for driving the first conveyor unit when the rotor (9) is started in a first direction of rotation and for driving the second conveyor unit when the rotor (9) is started in a second direction of rotation; a control unit (4) for controlling the motor (6) for delivering the first detergent from the first container (25) into the lye container (5) by means of the first delivery unit or the second detergent from the second container (26) by means of the second delivery unit as a function of the release, wherein the rotor (9) starts up randomly in one of two directions of rotation when the stator winding (11) is charged with electrical energy, wherein a sensor unit (24) having two sensor elements (22, 23) and being connected to the control unit (4) is provided, wherein the sensor elements (22, 23) are arranged at a distance from one another in the circumferential direction, in which case the angle between the respective radial connecting lines of the two sensor elements (22, 23) to the axis of rotation (10) of the rotor (9) differs from the angle of the two sensor magnets (b) 14) An angle between the respective connecting lines to the rotational axis (10) or an angle different from an integer multiple thereof, and the sensor elements (22, 23) are positioned relative to the rotor (9) such that they sense the magnetic field of the sensor magnet (14), wherein the control unit (4) is designed to determine the rotational direction of the rotor (9) by evaluating the sensor signals of the sensor elements (22, 23) and to repeat the activation of the electric motor (6) for a long time until the rotor (9) is activated in a predefined rotational direction in order to supply the detergent from the one of the first and second containers (25, 26) which is predefined by the release into the lye container (5).